Chlorofluoromethane is one of the substances that contribute to the destruction of the ozone layer.

I enjoyed the beautiful rural scenery while walking along the ridge.

Ogura Hyakunin Isshu is one of the classical literatures of Japan.

He was anxious about starting a new business, but I encouraged him by saying, 'Even a journey of a thousand miles begins with a single step.'

World War I was a large-scale war that lasted from 1914 to 1918.

This mutetrahedron plays a very important role in the world of mathematics.

This is a model of a mutetrahedron.

This mutetrahedron has a very unusual shape.

He tried to work hard and study at the same time, and in the end, he experienced the lesson of 'He who chases two hares catches neither.'

His success is an example of the proverb 'one general achieves success at the cost of ten thousand bones'.